20785720 has 16 divisors (see below), whose sum is σ = 46767960. Its totient is φ = 8314272.

The previous prime is 20785693. The next prime is 20785733. The reversal of 20785720 is 2758702.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 259782 + ... + 259861.

Almost surely, 2^20785720 is an apocalyptic number.

20785720 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

20785720 is an abundant number, since it is smaller than the sum of its proper divisors (25982240).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

20785720 is a wasteful number, since it uses less digits than its factorization.

20785720 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 519654 (or 519650 counting only the distinct ones).

The product of its (nonzero) digits is 7840, while the sum is 31.

The square root of 20785720 is about 4559.1358830375. The cubic root of 20785720 is about 274.9508231624.

The spelling of 20785720 in words is "twenty million, seven hundred eighty-five thousand, seven hundred twenty".